Tiempo de contagio de pacientes con SARS-CoV-2: un análisis a diez meses de la pandemia

Under the current circumstances of the COVID-19 pandemic and given the possibility of collapse of health systems due to the increase in infections worldwide, it is necessary to establish the time in which a patient infected with SARS-CoV-2 maintains the contagious condition. Determining the infectious agent's transmissibility phase with greater precision will serve to standardize the isolation period of the patient and will prevent the spread of the virus at the community level and its safe return to work. Through molecular tests it has been established that viral RNA is detectable in the respiratory tract from 2 to 3 days before the manifestation of symptoms, reaching its maximum level at the onset of symptoms and decreasing progressively in the following 7 or 8 days in most of patients. However, persistent detection of viral RNA by RT-PCR does not necessarily mean that the patient remains infectious. It has been reported that in mild and moderate cases of COVID-19, the repli-cative capacity of the virus lasts until day 9 from the onset of symptoms, while, in severe and critical cases, it lasts until day 20 from the onset of symptoms. Currently, the strategies proposed by the WHO and the CDC to define the isolation time of those infected are based on the time of manifestation of symptoms and the clinical evolution of the patient.